Description

These routines set options that deal with output within curses. All options
are initially FALSE, unless otherwise stated. It is not necessary to turn
these options off before calling endwin().

With the clearok() routine, if enabled (bf is TRUE), the next call
to wrefresh() with this window will clear the screen completely and redraw
the entire screen from scratch. This is useful when the contents of
the screen are uncertain, or in some cases for a more pleasing visual
effect. If the win argument to clearok() is the global variable curscr(),
the next call to wrefresh() with any window causes the screen to
be cleared and repainted from scratch.

With the idlok() routine, if enabled (bf is TRUE), curses considers using
the hardware insert/delete line feature of terminals so equipped. If disabled (bf
is FALSE),curses very seldom uses this feature. (The insert/delete character
feature is always considered.) This option should be enabled only if the
application needs insert/delete line, for example, for a screen editor. It is
disabled by default because insert/delete line tends to be visually annoying when used
in applications where it isn't really needed. If insert/delete line cannot be
used, curses redraws the changed portions of all lines.

With the idcok() routine, if enabled (bf is TRUE), curses considers using
the hardware insert/delete character feature of terminals so equipped. This is enabled
by default.

With the immedok() routine, if enabled (bf is TRUE), any change in
the window image, such as the ones caused by waddch(), wclrtobot(), wscrl(),
etc., automatically cause a call to wrefresh(). However, it may degrade the
performance considerably, due to repeated calls to wrefresh(). It is disabled by
default. Normally, the hardware cursor is left at the location of the
window cursor being refreshed. The leaveok() option allows the cursor to be left
wherever the update happens to leave it. It is useful for applications
where the cursor is not used, since it reduces the need for
cursor motions. If possible, the cursor is made invisible when this option
is enabled.

The setscrreg() and wsetscrreg() routines allow the application programmer to set a
software scrolling region in a window. top and bot are the line
numbers of the top and bottom margin of the scrolling region. (Line 0
is the top line of the window.) If this option and scrollok()
are enabled, an attempt to move off the bottom margin line causes
all lines in the scrolling region to scroll up one line. Only
the text of the window is scrolled. (Note that this has nothing
to do with the use of a physical scrolling region capability in the
terminal, like that in the VT100. If idlok() is enabled and the
terminal has either a scrolling region or insert/delete line capability, they will
probably be used by the output routines.)

The scrollok() option controls what happens when the cursor of a window
is moved off the edge of the window or scrolling region, either
as a result of a newline action on the bottom line, or
typing the last character of the last line. If disabled, (bf is
FALSE), the cursor is left on the bottom line. If enabled, (bf
is TRUE), wrefresh() is called on the window, and the physical terminal
and window are scrolled up one line. (Note that in order to
get the physical scrolling effect on the terminal, it is also necessary to
call idlok().)

The nl() and nonl() routines control whether newline is translated into carriage
return and linefeed on output, and whether return is translated into newline
on input. Initially, the translations do occur. By disabling these translations using
nonl(), curses is able to make better use of the linefeed capability,
resulting in faster cursor motion.

Return Values

setscrreg() and wsetscrreg() return OK upon success and ERR upon failure. All
other routines that return an integer always return OK.